ADCs have improved safety and proven clinical efficacy
ADCs are an important, emerging class of biopharmaceuticals. Harnessing the specificity of an antibody to the mechanism-of-action-specific potency of a small molecule drug to achieve targeted cell death, ADC therapeutics have a predicted market worth of approximately $10 billion by 2025.1
To date, ADCs have mainly been designed to deliver cytotoxic agents to tumor cells, with five ADC drugs granted approval for oncology indications within the last decade.2,3 Additional non-cytotoxic classes of ADCs are under development that incorporate antibiotics or steroids that target infectious or inflammatory diseases, respectively.4,5 Since ADCs offer considerable therapeutic promise for life-changing diseases, speed to market remains essential. However, ADC production is associated with several common challenges:
• Supply chain complexity, requiring multiple manufacturing facilities to produce the antibody, drug-linker, ADC, and final drug product
• Safe handling practices, both to protect the biologic product from contamination as well as to protect manufacturing personnel from the potent small molecule component
• Product heterogeneity, requiring analytical tools that are capable of resolving different product variant populations, as well as manufacturing processes with the capacity to control them
To mitigate risk and assure product safety, efficacy, and supply, it is important to partner with a trusted CDMO experienced in these critical aspects, and to maintain and cultivate the strategic partnership throughout the entirety of the ADC lifecycle.
Accelerated approval reduces development timelines
The FDA has introduced four approaches to expedite the availability of therapeutics: Fast Track, Breakthrough Therapy, Accelerated Approval, and Priority Review.6 To meet accelerated program timelines, an experienced CDMO can expedite a drug development program through all lifecycle stages, including stage 1 – process design; stage 2 – process qualification; and stage 3 – continued process verification.7
By properly leveraging prior knowledge, existing best practices, and platform process/analytical techniques, a strategic partnership can help navigate the accelerated timelines to keep CMC activities and product supply off the critical path. Furthermore, by completing CMC activities earlier, a more robust stability package may be included in the CMC dossier which could allow for improved shelf-life being approved for the product.
Strategic supplier selection expedites commercial readiness and shortens supply lead times
To prevent unnecessary delays, it is prudent to begin ADC manufacturing at the commercial site as early as possible. This enables a multi-stage process characterization program to start earlier in the development cycle, avoiding the need for tech transfer at a late phase and eliminating the requirement to perform laborious and time-consuming comparability studies prior to regulatory submission. Furthermore, the likelihood for CMC success can be increased by partnering with a CDMO experienced in analytical techniques, process characterization, process validation, comparability, and regulatory submissions.
ADC product supply lead times can also be reduced by selecting a CDMO able to manufacture multiple components of the ADC. A partner with the capability to perform multiple manufacturing steps affords reduced lead times by enabling further processing based on a subset of analytical release testing, elimination of shipping raw materials and/or intermediates, and flexible scheduling to accommodate raw material readiness and operating under one quality system. When selecting an integrated CDMO it is critical that they have strong program management to ensure all components of the development program are working in harmony.
Planning process characterization strategy and timing relative to PPQ is advantageous
Process characterization is an essential component of the process validation lifecycle, employing multiple activities to develop product and process control strategies. It typically begins following phase II clinical trials. However, if process characterization is brought forward to phase I, development plans can support a PPQ earlier on. This requires a clear strategy for the design and timing of experiments and analytical method development.
A primary aim of process characterization is to ensure that process robustness is suitable to deliver a quality target product profile (QTPP) appropriate for commercial launch. To achieve this, a control strategy is created to meet the QTPP by determining critical quality attributes (CQAs) which are known or highly likely to impact safety or efficacy. Control points are established which ensure the CQAs and thus the QTPP are met, including material inputs, critical process parameters (CPPs), proven acceptable ranges (PARs), in-process controls (IPCs), and release / stability testing.
To compress program timelines further, process characterization activities may be tiered to have some overlap with PPQ runs. PPQ is a component of process validation which is typically performed following process characterization, yet a tiered approach to product characterization enables PPQ to be carried out much earlier. As an example, process characterization activities may be categorized as two tiers. Early tier range-finding studies can be used to define PARs and to identify parameters which should be monitored during validation (e.g. likely CPPs), enabling PPQ runs to go ahead. Later tier studies may then be performed in parallel with, or following, PPQ.
It is important to note this strategy may result in the need for additional studies should unexpected findings occur during or post-PPQ, therefore it is best applied to a situation in which a robust platform process is already in place and extensive manufacturing experience is available to reduce the risk. Utilizing prior knowledge to determine CQAs, CPPs and non-critical process parameters (NCPPs), a tiered approach to process characterization can be highly successful.
Acceleration relies on strong analytical understanding
The use of representative laboratory scale-down models (SDMs) to deliver strong analytical understanding is pivotal to establish QTPP. These may include appropriate scale-down models for conjugation and purification, and small-volume liquid handling robots for chromatography. Allowing multiple experiments to be performed in parallel, these systems are used to define those parameters which significantly impact CQAs and to eliminate those which have little effect. Studies which are performed include range-finding, process mapping, impurity spiking/clearance studies, resin/membrane cleaning/storage studies, resin/membrane aging studies, virus clearance validation studies and leachable/extractable analyses.
In addition to being vital to process characterization, analytical methods are employed within other stages of process validation, including structural elucidation, extended characterization for comparability, and QC release. A thorough understanding of a molecule’s structure-function relationship may guide the development process and potentially reduce the total number of studies.
With such a depth of analytical understanding required for approval, accelerated commercial development schemes are best-suited to organizations experienced in analytical method development and application. Upfront investment in such a multitude of analytical methods can often be prohibitive for less experienced organizations. Forthose organizations with the capacity to leverage platform methods and prior knowledge, it is often less likely that they encounter the need to implement analytical method changes later in development, an activity which can be hugely detrimental to timelines.
Robust comparability strategy is key to support the validation lifecycle
A caveat of accelerated approval is that there is often little time to fully optimize the process prior to launch (e.g. for cycle times or yields), and as well, with limited batch history, a strong stage 3 continued process verification plan is key to ensure the control strategy developed during stage 1 and proven in stage 2 remains in a state of control. Robust comparability studies are essential to support changes which occur both pre- and post-approval. These can be streamlined by partnering with a CDMO experienced in defining comparability strategies and delivering comparability data. A strong comparability package empowers organizations to implement new technologies to enhance process robustness, improve product yield, or reduce cycle time.
Your partner for ADC development and manufacturing
AbbVie Contract Manufacturing leverages comprehensive experience to provide partners with unparalleled expertise in delivering launch-ready ADCs that can support accelerated timelines: from analytical understanding, a well-defined process characterization strategy that enables PPQ, manufacturing expertise, process validation and comparability strategies, to regulatory submissions. For an ADC or biologics program at any stage, AbbVie can assist in achieving your CMC deliverables, timelines, and budget. For more information on capabilities, visit AbbVie CMO at www.abbviecontractmfg.com or reach us at 1-847-938-8524.
2) Antibody-Drug Conjugates: Pharmacokinetic/Pharmacodynamic Modeling, Preclinical Characterization, Clinical Studies, and Lessons Learned, Hedrich WD et al, Clin Pharmacokinet. 2018 Jun;57(6):687-703
4) Antibody-drug conjugates for non-oncological indications, Liu R et al, Expert Opin Biol Ther. 2016;16(5):591-3
5) Immunoregulation by IL-7R-targeting antibody-drug conjugates: overcoming steroid-resistance in cancer and autoimmune disease, Yasunaga M et al, Nature Scientific Reports volume 7, Article number: 10735 (2017)